BKT phase transition in nanoporous films of superconducting NbN

Fuente: arXiv
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Main Authors: Verma, A., Vedin, R., Jesudasan, J., Lidmar, J., Maccari, I., Bose, S.
Format: Preprint
Published: 2024
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author Verma, A.
Vedin, R.
Jesudasan, J.
Lidmar, J.
Maccari, I.
Bose, S.
author_facet Verma, A.
Vedin, R.
Jesudasan, J.
Lidmar, J.
Maccari, I.
Bose, S.
contents We present a study of the Berezinskii-Kosterlitz-Thouless (BKT) transition in mildly disordered NbN nanoporous (NP) films. The measured superfluid stiffness, Js, is found to be much lower than that predicted by considering the reduction in the geometric area. This effect is also reproduced theoretically via Monte Carlo simulations on a 2D XY model with different nanopore geometries. For a 5 nm thick NP film, a distinct BKT transition is observed. BKT renormalization group flow equations, incorporating the broadening in Js due to the presence of inhomogeneities, are used to fit the experimental data. From this analysis we see that both Js and the vortex core energy, mu, decrease in the presence of nanopores. Our results show that nanopore geometries effectively enhance the 2D nature of the films, thereby increasing the parameter space to explore BKT physics in superconducting films.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22704
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle BKT phase transition in nanoporous films of superconducting NbN
Verma, A.
Vedin, R.
Jesudasan, J.
Lidmar, J.
Maccari, I.
Bose, S.
Superconductivity
We present a study of the Berezinskii-Kosterlitz-Thouless (BKT) transition in mildly disordered NbN nanoporous (NP) films. The measured superfluid stiffness, Js, is found to be much lower than that predicted by considering the reduction in the geometric area. This effect is also reproduced theoretically via Monte Carlo simulations on a 2D XY model with different nanopore geometries. For a 5 nm thick NP film, a distinct BKT transition is observed. BKT renormalization group flow equations, incorporating the broadening in Js due to the presence of inhomogeneities, are used to fit the experimental data. From this analysis we see that both Js and the vortex core energy, mu, decrease in the presence of nanopores. Our results show that nanopore geometries effectively enhance the 2D nature of the films, thereby increasing the parameter space to explore BKT physics in superconducting films.
title BKT phase transition in nanoporous films of superconducting NbN
topic Superconductivity
url https://arxiv.org/abs/2410.22704